Semi-Regular Structures Inside Random Turbulent Flow

Xiaohua Wu (Xiaohua.Wu@rmc.ca) Department of Mechanical Engineering Royal Military College of Canada

Parvis Moin Center for Turbulence Research, Stanford University

When fluid flows over a wing or over a flat-plate, quite often the state of the flow transitions from regular (laminar) to chaotic (turbulent). Even though we cannot easily see with our naked eyes, inside the seemingly random turbulent flow amazing semi-regular structures do exist. For instance researchers have reported signatures of hairpin-like vortex structures from turbulent boundary layer over a flat-plate.

These three images were extracted from a numerical simulation of the flat-plate boundary layer, which grows from laminar through transition to turbulent. It is very interesting to observe the forest of hairpins in the chaotic turbulent state

This work was supported by DOE (USA) and NSERC (Canada).

These images have not yet been published, though they are part of a manuscript that is under review.